# Glossary

> Terms used in UAE e-invoicing and in this documentation.

Source: /docs/reference/glossary

| Term | Meaning |
| --- | --- |
| **ASP** | Accredited service provider: a company accredited by the UAE Ministry of Finance to validate, exchange and report e-invoices. Alya Books submits through Taxilla. |
| **BT / BG** | Business term / business group: numbered data elements of EN 16931 and PINT (`BT-31` seller TRN, `BG-25` invoice line). |
| **Credit note** | Document type `381` that reduces or cancels an issued invoice; references the original with BT-25/BT-26. |
| **Debit note** | Document type `383` that increases an issued invoice. |
| **Delivered** | The buyer's access point accepted the document (corner 3 → 4). |
| **EN 16931** | The European semantic model for e-invoices that PINT builds on. |
| **Id** | The UUID of an object (`id` in responses; `invoiceId` where a response refers to an invoice). |
| **FTA** | Federal Tax Authority of the UAE, corner 5 of the model; receives the tax data. |
| **Incoming invoice** | A document received from a supplier (accounts payable). |
| **Live / test key** | `sk_live_…` creates real documents; `sk_test_…` creates test documents that never reach the live ASP. |
| **Metadata** | Custom field values (`metadata: { key: value }`) defined by templates. |
| **Outgoing invoice** | A document issued by the organization (accounts receivable). |
| **Peppol** | The network and standards used for exchange; participants are identified by scheme `0235` and their 10-digit TIN (the first 10 digits of the TRN) in the UAE, for example `0235:1002345678`. |
| **PINT AE** | The UAE specialisation of the Peppol International Invoice model (`urn:peppol:pint:billing-1@ae-1`). |
| **Reported** | The FTA accepted the tax data; invoice status `accepted`. |
| **Review status** | Internal approval state (`none`, `pending`, `approved`, `declined`); pending or declined blocks submission. |
| **Scope** | Permission attached to an API key (`invoices:write`, `webhooks:manage`, …). |
| **Series** | A numbering sequence per document kind with a template such as `INV-{YYYY}-{n}`. |
| **Transaction type** | UAE classification of the supply (`standard`, `free_trade_zone`, `exports`, …) written into the XML. |
| **TRN** | Tax Registration Number, 15 digits, issued by the FTA. |
| **UBL** | Universal Business Language, the XML syntax used by PINT AE (Invoice and CreditNote documents). |
| **Validation** | The PINT AE business-rule check Alya Books runs before storing or submitting an invoice. |
| **Webhook** | An https endpoint that receives signed event notifications. |